Diorganotin di(thioalkylene carboxylic acid esters)and the preparation thereof



United States Patent DIORGANOTIN DI(THIOALKYLENE CARBOXYL- IC ACID ESTERS) AND THE PREPARATION THEREOF Toshio Seki, Osaka-shi, and Kozaburo Suzuki, Kobe-shi, Japan, assignors to Nitto Kasei Co., Ltd., Osaka, Japan, a corporation of Japan No Drawing. Original application May 16, 1967, Ser. No. 638,774. Divided and this application June 26, 1969, Ser. No. 851,120

Int. Cl. C07f 7/22 US. Cl. 260-429.7 Claims ABSTRACT OF THE DISCLOSURE Sulfur containing organotion compounds of the formula R Sn[S(CH COO(CH CH O),,Y]

prepared by the reaction of an ester and a dialkyltin oxide may be used as stabilizers for resins.

This application is a division of co-pending application Ser. No. 63 8,774, filed May 16, 1967, and now abandoned.

This invention relates to novel sulfur containing organotin compounds, to the preparation of such compounds, and to polyvinyl chlorides, copolymers with vinyl chlorides as the main constituent, or these resinsbased polyblends, stabilized with said sulfur containing organotin compounds.

There have been heretofore used a number of different types of sulfur-containing.organotin compounds known as stabilizers for these resins (as are disclosed in Japanese patent publications Nos. 789/57, and 5282/59), but these conventional stabilizers may be characterized by unsatisfactory stabilizing ability because of volatilization during the process of producing resins at elevated temperatures, and since they possess a sharp odor characteristic of mercaptan, not only do they make op erators feel uncomfortable, but they often give a bad influence to the human body. In addition, as these stabilizers may not prevent a resinous composition containing same from adhering to a roll, and also may not reduce a gelling time, it is hard to conduct operations efficiently or handily for prolonged periods of time without the aid of supplementary stabilizers. Furthermore, halogen containing resins often undergo a change of physical properties (e.g. increasing of fragility) by the addition of these sulfur containing organotin compounds.

According to the present invention, these adverse effects may be reduced or eliminated by employing a new class of sulfur containing organotin compounds as stabilizers.

It is an object of this invention to provide novel sulfur containing organotin compounds and methods of producing such compounds. A further object of this invention is to provide polyvinyl chlorides, copolymers with vinyl chlorides as the main constituent, or these resinsbased polyblends, stabilized with these novel sulfur containing organotin compounds. Other objects will be apparent to those skilled-in-the-art from the following description.

In accordance with certain of its aspect, the method of this invention for stabilizing polyvinyl chlorides, copolymers with vinyl chlorides as the main constituent, or

3,525,760 Patented Aug. 25, 1970 ice those resin-based polyblends against the deteriorating effects of heat and light comprises incorporating into said halogen containing vinyl resins an inhibiting amount of a sulfur containing organotin compound having the following formula R Sn [S (CH COO (CH CH O Y] 2 wherein R is alkyl of 1-8 carbon atoms, m and n are each integers from 1 to 2, inclusive, and Y is selected from the group consisting of alkyl of 1-8 carbon atoms, and phenyl.

Since a sulfur containing organotin compound employed in the invention has at least two ether linkages in its molecule, it is less volatile than the conventional stabilizers, and the liability of the sulfur containing organotin compound in a resin composition to escape therefrom is much less than that of the conventional stabilizer. The low volatility of the sulfur containing organotin compounds make them especially useful as stabilizers in halogen containing vinyl resin formulations which require heat or exposure to elevated temperatures during use or during the processing of the halogen containing vinyl resin material. At the same time since the sulfur-containing organotin compounds have both ester and ether linkages in their molecules, these novel stabilizers may exhibit a good compatibility with resins and an accelerated gelation; they may make the lowest processable temperature of resins reduced about 5 C. compared with the conventional stabilizers; and resin compositions containing said novel stabilizers may perform over longer periods of time during the heat processing of same. A new class of these compounds also may impart an improved satisfactory stabilizing effect against degradation by light to resins compared with the conventional sulfur-containing organotin compounds which are unstable to light. Besides, there is not practically a disgusting smell of mercaptan during the process of producing stabilized resins, and consequently they do not affect badly to a person.

Specific examples of the sulfur-containing organotin stabilizers which are within the scope of this invention include, among others, the following:

In acordance with certain aspects of this invention, the method of preparing sulfur-containing organotin compounds comprises the steps of:

(a) Reacting an ethanol derivative having at least two ether linkages therein, e.g. methyl Cellosolve, ethyl Cellosolve, isopropyl Cellosolve, butyl Cellosolve, phenyl 4 Cellosolve, methyl Carbitol, ethyl Caribtol, and butyl Car observed. The same sheets prepared for a weathering test bitol, with a mercapto acid, e.g. thioglycolic acid, and B- were irradiated for 500 hours in a weatherometer, equipmercaptopropionic acid by the conventional method to ped with a xenon lamp which is screened by a heat resistform an ester, ing optical glass filter in order to cut off ultraviolet rays (b) Heating with stirring said ester and a dialkyltin below the wave-length of 279 my, and the discoloration oxide, e.g. dimethyltin oxide, dibutyltin oxide, diamyltin and the deterioration other than that in appearance were oxide, and dioctyltin oxide in the presence (or absence) observed. For volatility the stabilizers were tested by of an inert solvent, and weighing precisely each of compounds (A) and (B) in (c) Removing water formed in the reaction. dishes; heating the dishes to 180 C. in a Geer oven for Only an inhibiting amount of organotin compound is 1 hour; and measuring the weight loss. Results are shown required. Preferably, the amount of the sulfur containing in the following Table I.

TABLE I Test for weatherability Test for heat stabilityColor of sheet aiter- Heating loss Color of sheet Appearance of of stabilizer Stabilizer 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 500 hrs. sheet after 500 hrs. (percent) (A) Colorless Cnlmlm: Colorless Light yellow Colorless No erazing O. 4 (B), do do Light yellow Yellow Brown A iewlines of 3. 0

erazing.

organotin stabilizers to be employed in the process of this Moreover, in order to prove a good workability of resinvention is in the range of 0.1 to 10 parts by weight per inous composition containing the stabilizer of this inven- 100 parts by weight of the resins. The stabilizers may be tion, a test was conducted to determine the lowest posused singly or in combination, and they may also be sible surface temperature of a roll so that a completely used together with other known stabilizers, and with other gelatinated transparent sheet might be obtained. Procadditives such as a mold lubricant, an antioxidant, and a essing at 145 C. was suflicient to make such a sheet in U.V. absorber. the case of using stabilizer (A), whereas in the case of EXAMPLE 1 using stabilizer (B), processing even at 150 C. was not sufficient. It is a great advantage to be able to lower a processing temperature by 5 C. in the process of molding heat sensible polyvinyl chlorides.

A three-necked flask, equipped with a stirrer and a Dean trap, was charged with 1.1 mole of thioglycolic acid, 1 mole of butyl Cellosolve, 200 ml. of benzene as solvent, and 1.2 g. of p-toluenesulfonic acid as esterification EXAMPLE 2 catalyst. This mixture was reacted by the conventional In a manner similar to that of Exam 1e 1 but 1 Cap mathod to form 180 (935%) of P cengsolve g bitol thioglycollate 'was synthesized by the ieaciion of gfilyionate .(HSCH2POOCHECHZOC4 A t reenec ed butyl Carbitol and thioglycolic acid, and 0.5 mole of said as equipped wlth a Super and a D can l was butyl Carbitol thioglycollate was allowed to react with charged with 0.5 mole of said ester, 0.25 mole of dibutyl- 025 mole of dioctyltin oxide to yield 200 g (98 0% of tin oxide, and benzene as solvent. This mixture was heated dioctyltin bis (butyl Carbitol thioglycollate) with stirring until all the water of reaction was removed. The benzene was then distilled off under reduced pressure a 17)2 2 2 2' 2 2 4 9)2 to yield 153 g. (99.5%) of dibutyltin-bis-(butyl Cellosolve (c The roduct is a ht euow, trans arent H thioglycollate), (C H Sn(SCH COO-CH CI-l OC H 2 physical properties; IZODZIAQZG; 3( 1 1()4, (A). The product is a colorless, transparent liquid. The 5 Analysis calculated (percent): Sn 145; S, 736.

p y P p 3o 4 Found (percent): Sn 14.9- s 7.71.

y- (E S, A mixture of 100 parts by weight of copolymer con- Found (P r -i S11, 1040- sisting of by weight of "vinyl chloride and 5% by To parts by weight of polyvinyl chlo (111F311 weight of vinyl acetate, and 3 parts by weight of said polymerlzatlon degree: was added 2Parts y welght 55 compound (0), and a mixture, for comparisons, of 100 of sa1d dibutyltm-bls-(butyl Cellosolve thioglycollate) (A)- parts by weight of said copolymer and 3 parts by Weight The mixture was sheeted by milling for 5 minutes on a f dioctyltin bis (octyl thioglycollate) mixing roll heated to l60i2 C. For comparative purposes, by the same procedure, a sheet was made contain- (csHl'l)2Sn(SCH2COOc8H17)2 ing 2 parts by weight of dibutyltin didodecyl mercaptide, 60 (D) were sheeted by milling for 5 minutes on a mixing (C H Sn(SC H (B) as PIIOI art sulfur containing roll heated to :2" C. The sheets were tested for stabilizer in place of the stabilizer of this invention. heat stability and weatherability, and the stabilizers test- The obtained sheets were tested in a Geer oven heated ed for volatility in a manner similar to that of Example to C. for heat stability, and the discoloration was 1. Results are shown in Table 11.

TABLE II T ti n Test for heat stability-Color of sheet afterw Heating loss Color of sheet A earanee of i t bl' Stabilizer 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 500 hrs. sh e t after 600 hrs. 0 lpire r ig (C) Colorless Colorless Light yellow Yellow Light yellow Almost no ea in (D) do Light yellow Yellow Brown Livor-ooloredll': Entirely fine 2 2:?

crazing.

The same resin compositions as aforesaid were milled on a mixing roll heated to l50t2 C. until the sheets thus obtained become discolored light yellow. The stabilizer (C)containing sheet required blending for 19 minutes to be light yellow in color, whereas the stabilizer sulfur-containing organotin compounds having ether linkages in their molecules may impart a good gelatinousness and lubricity to vinyl chloride resins, they may inhibit the stay of a resinous composition in the extruder, the adhesion, and the thermal decomposition; consecutively op- (D)-containing one required blending for 13 minutes. 5 eratable time may be prolonged; and as a result, work- This demonstrates that novel stabilizer (C) may not only ability may be much improved.

impart good heat stability to a product, but it may pre- Thus obtained pipes were tested for heat stability and vent the resin composition from adhering to a roll, and weatherability by the same method as in Example 1, and makes it possible to set a roll in motion over a longer also loss on heating of stabilizers (E and (F) was measperiod of tlme. ured. Results are shown in Table III.

TABLE III Test for weatherability Test for heat stability A f Color of pipe Color of pipe pigg 0 Heatingglgss of S 1 128! Stabilizer After 0.5 hr. After 1.0 hr. After 1.5 hrs. After 2.0 hrs. After 500 hrs. After 500 hrs.. (percent) (E) Colorless Colorless Light yellow Yellow Light yellow. Transparent- 0.5 (F) do Light yellow Yellow Brown Liver-colored. Cloudy white.-- 2.3

EXAMPLE 3 The smell of molded pipes was then examined 5 hours fter extrusion-molding. The molded pipes containing In a manner similar to that of Example 1, 180 g. a 98.3%) of dibntylin bis-(butyl Carbitol-fi-mercaptoproiiiizitiz agin iiiid ig io iiiiniii i iiifi E iiia ci a t Plona much diminished odor of sulfur.

4 9)2 z z 2C 2 Z 2 4 B)2 Although this invention has been illustrated by refer- (E) was obtained from 0.25 mole of dibutyltin oxide and ence to Specific eXamples, rous changes and modi- 95 mole f butyl GarbimpgmercaptopropiOnate The iications thereof which clearly fall within the scope of the product is a light yellow, transparent liquid. The physical mventlol} W111 be PP to those properties: n =1.4981; D =1.152. What 1 1 611 181 Analysis-Calculated (percent): Sn, 16.2; S, 8.77. The Compound havlngthe formula Found (percent): Sn, 16.8; S, 8.54. r R S S CH COO CH CH O Y To 100 parts by weight of a polyblend consisting of 30 h R i i f i b 2 2 )n 12 95% by weight of polyvinyl chloride and 5% by weight t erem f 15 a 1 2 g on atoms and n are each of styrene-butadiene-acrylomtrile terpolymer, 3 parts by egers mm g and Y 15 Selected from weight of said compound (E) was added as stabilizer. For t 8 group conslstmg of a Y1 of 1-8 carbon atoms: and comparative purposes, to the coinciding amount of the 40 Z Yfi d I 1 same polyblend, the coinciding amount of dibutyltin-,8- e compoun as c almed m 6 31m 1 havmg the Inercaptopropionate formula (C H Sn (SCH COOCH CH O CH 2 S CH2 CH2 3. The compound as claimed in claim 1 having the 4 9)2 formula 0 0:0 (C H SI1(SCH COOCH CH OCH CH OC H was added as known sulfur-containing stabilizer in place s The compound as clalmed m claim 1 having the forof compound (E). These mixtures were blended on a Herschel mixer, and gelling point and time were measured. 4 9)2 2 2 2 2 2 2 4 9)2 The mixture containin stabilizer (E) got gelatinized at 5 The method of o o preparing the compound of cla1m 1 133 i f 6 i f and 30 secondszvifhereas the which comprises reacting an ethanol derivative having at ture contifumng stablhzer (F) got gelatmlzed 137 least two ether linkages therein, and a mercapto acid to after, 7 l and 15 g g Eacl? P the fi ig was form an ester; heating with stirring said ester and a dicontlnue o e compoun e y mixing uni ey were 31k heated to 150 C., and the mixtures were extrusiony mo 1 and removing water formedm the reactlon' molded into pipes of 25 mm. in the outside diameter and References Cited 15 mm. in the inside diameter by a screw extruder having a screw diameter of 65 mm. at an extruder head tempera- UNITED STATES PATENTS ture of 185 C. and at a cylinder temperature of 170 C. 2,832,751 4/1958 Weinberg 260-4297 X Each stabilizer-containing pipes were weighed after ex- ,115,509 12/1963 Mack 260429.7 trusion-molded for 2 minutes. The stabilizer (E)-contain- 3,478,071 11/ 96 e d 260-429-7 ing pipe weighed 680 g., whereas the stabilizer (F)-containing one weighed 590 g. Consecutively operatable time TOBIAS LEVOW, P lmary Examlnel of the extruder was also measured. When stabilizer (E) W BELLAMY, Assistant Examiner was employed as additive, the extruder could be operated more than 25 hours. On the other hand, when stabilizer US. Cl. X.R.

(F) was employed, the extruder could be operated only 26045.75 4 hours. As is apparent from the above results, since 

